Editorial

Nicholas Enticknap, Editor

This issue of Resurrection is the largest we have yet
produced, reflecting the fact that the Society has been
through a most eventful period. The most significant
development has been a change in our relationship with the
Science Museum, which has resulted in the movement of most of
our restoration activity to Blythe House, Olympia, and of the
secretariat to Tony Sale's home in Bedfordshire. It will take
time to work out the full effect of these changes: the
position as we know it at the moment is described by Tony on
page 5 and by Doron Swade on pages 7-11.

Sadly, we have to record the death of one of our leading
lights, John Cooper. John was the leader of the highly
successful Pegasus restoration project, the most celebrated of
the Society's achievements. Chris Burton, a member of John's
team who has taken over his responsibilities as working party
chairman, pays tribute to John on page 12.

The Society now has a second Pegasus restoration project under
way, this time in conjunction with the Manchester Museum of
Science and Industry. This provides members in the north-west
with an opportunity to take part in a restoration project for
the first time. Further details can be found in Society News.

This makes it an appropriate time to recount the Pegasus
design story. Ian Merry's description of the process is one of
three feature articles in this issue. The others desibe the
development of the Society's totalisator, and the problems and
issues that face us in our attempts to preserve software. We
also publish three letters from readers, all responding to
items that appeared in previous issues. We welcome such
letters, especially when it is a question of putting the
record straight.

We are grateful for the good response to our plea in issue 6
for help with the Society's archiving project. We now have
another opportunity for members who would like to play a part
in our activities but who do not have technical or engineering
skills.

Pat Woodroffe has painstakingly produced transcripts of nearly
every one of our talks and seminars since the Society was
formed in 1989. He now feels he would like some assistance
with this task. Any member who has an audio cassette recorder
and a word processor and would like to help should contact him
direct, or alternatively the Secretary. Contact information
can be found inside the back cover.

Guest Editorial

Sandy Douglas, Committee member

At the age of eight my parents brought me to live in Cromwell
Road, near what used to be the London Air Terminal, only it
was open space then. A 74 bus ride for one old penny took me
to Exhibition Road, from which I could go towards South
Kensington station to my father's office (which is still
there) and workshop (now demolished) down by what became the
Elysée Française. Alternatively, I could turn north to the
Science Museum - a trip I took often.

The winter of 1938-39 sticks particularly in my memory,
because we had a white Christmas, and my girlfriend (now my
wife) and I made a snowman in the grounds of the Natural
History Museum, near the tunnel exit. The tunnel is now much
as it was then, except for the mosque exit.

In those days the special attraction of the Science Museum for
me was the basement room where the working models were on
display. One could learn about various methods of pumping up
water by turning handles or pressing buttons. Some, like the
Archimedes screw, are still in use on the Nile today. There
was also a colour spectrum to look at, from which I learned
that two people did not necessarily have the same perception
of colours - my wife and I still argue about the blue/green
interface we discovered we viewed differently.

During the Blitz in 1940-41 my Home Guard Unit, 'C' Company of
the Chelsea and Kensington Battalion of the KRRC, had its
headquarters in the basement of the Royal School of Mines,
just the other side of Exhibition Road from the museums. We
were never actually called out to protect them - my duties
mostly took me to the north end of Albert Bridge where we had
a defence post, or riding around on a bicycle as a messenger.

Many of the staff were engaged in fire watching, of course,
and crossing the road at night was hazardous due to the
occasional bit of shrapnel from our own A-A which was more
liable to fall on one than a bomb. Luckily the Museum - and my
favourite room - survived reasonably intact.

Things have changed at the Museum, and a much expanded do-it-
yourself section on the first floor delighted two of my
grandsons when I took them there recently. The Director and
his staff are to be congratulated on the attractive way in
which things are presented. Doron Swade has been a splendid
contact point for the CCS and has initiated us into the
preservation 'rules' for equipment. Given this background, it
has been an especial pleasure for me to take part in the work
of the CCS and help to preserve working artefacts from an
earlier stage of our industry.

The Pegasus holds an especial place in my affection, it being
the machine I installed as the central University machine in a
disused chapel in Leeds in 1957 - it was known as Lucifer, for
Leeds University Computing Installation
(FERranti). Our au
pair girl from Spain made a beautiful little devilish doll
which decorated the machine - it has probably disappeared by
now.

In 1980 I worked out that an Apple with two floppy disc drives
was about 300 times as powerful as the Pegasus at 1/300th of
the cost. Today we can assume that a further reduction of 100
times in cost per operation has taken place, though I haven' t
done the sums with a 486-based micro. We must also bear in
mind that the Pegasus represented an improvement of at least
tenfold in cost per operation over earlier machines. An
industry that has reduced its cost per operation by a factor
of 10 million or so over 45 years is surely unique and
certainly not easy to keep pace with mentally.

We are now faced with the problem of what to do about
software. The article, like a book, is easy to 'preserve', but
to run it requires the original hardware or an emulator.

Martin Campbell-Kelly has built an emulator of EDSAC I, and
can run the programs on it. But it is difficult, even
impossible, to give the flavour of what they did without the
photoreader and the screen, since the ability to use these as
input or output in unconventional ways, as in my noughts and
crosses program where the players interrupted the light beam
to input a move and viewed the storage monitor to see the
'board', cannot readily be reproduced on the emulating
equipment.

The matter becomes even more awkward with micros, where
programs of similar nature, eg Wordstar, Wordperfect and Word,
have been implemented on several different machines so as to
look as nearly alike as possible to the user. No doubt this
will be taken up by the CCS Working Parties in due course and
some solutions found for working presentations, which must be
our aim.

All of us on the Committee look forward to welcoming
assistance from whatever quarter, in our efforts to carry
forward a memory of this fascinating and fast changing
industry in working order!

Society News

Tony Sale, Secretary

There has been a significant change in our affairs since the
last issue. The Science Museum needs the space in the Old
Canteen building where we have been working since the CCS was
formed in 1989, and we have accordingly now moved to a new
location: Blythe House, which is in Blythe Road, Olympia,
London W14.

We have moved most of our computers and associated equipment
to Blythe House already. Some equipment which is not
immediately needed has been moved temporarily to premises in
Bletchley Park.

Pegasus is also an exception, as it is far too delicate to be
moved unless absolutely necessary. It will remain where it is
until the Museum decides on its final resting place: we hope
this will be in a new gallery in the Museum, though this
development has not yet been authorised.

The archive held jointly by the CCS and the Museum has also
remained in situ, pending the completion of a new
documentation centre in the basement of the Museum, which is
scheduled for October. Our archiving work, however, has had to
stop for the time being.

The move has meant a number of changes. Until we have settled
in, we shall not be running our In Steam days, and we have
also had to abandon our plans for an Open Day this year. In
addition, I shall now be running the secretariat from home
rather than from the Museum: the new contact details are
printed overleaf.

Our meetings and seminars will still take place at the Science
Museum as before. Details of the planned programme for the
autumn can be found on page 44.

The new Manchester Group of the Society is now fully in
operation. We have been fortunate in securing the services of
two well-known computing personalities to act as the inaugural
principal officers.

Peter Hall is the chairman: many will remember him from his
days as a senior executive at first Ferranti and then ICL, and
will recall his entertaining and informative talk at our all-
day Manchester seminar two years ago. Liz Segal is the
secretary: active in BCS circles for many years, Liz has
recently taken up a post at the IT Institute of the University
of Salford.

The new group's first activity is the restoration of the very
first Pegasus, which was moved from store into a gallery in
the Manchester Museum of Science and Technology in early July.

Another project that this group plans to undertake is the
construction of a replica of the Manchester University
prototype machine of 1948. The group also plans to run a
meetings programme. Volunteers are urgently needed to help
with all of these activities. So anyone in the north-west who
feels ready to take a more active part in the Society now has
the opportunity: they should contact Liz Segal on 061 745
5665.

New contact point

Readers wishing to contact the Secretary should note that
he is now running the secretariat from his home, and can
no longer be contacted at the Science Museum.

The CCS and the Science Museum - what now?

Doron Swade

Tony Sale has been at the centre of the computer restoration
activities at the Science Museum since the founding of the
Computer Conservation Society (CCS) in November 1989. It is
now perhaps well known that Tony vacated his office in The Old
Canteen (which has served as the home of the restoration
activities at South Kensington) when his current contract with
the Science Museum expired at the end of July.

Tony has been on a series of fixed term contracts which at
intervals came up for renewal. In the past, alarms of
impending doom were invariably followed by the relief of
reprieve. Having survived the threat of severance several
times we acquired a sense of security and a belief in the
inevitability of our own survival as the achievements of the
CCS became increasingly demonstrable and the Society continued
to thrive. I wish to register the disbelief and
incomprehension felt by everyone associated with the CCS
activities at the Science Museum that this time there was no
rescue.

With Tony's departure ends the first era in the comparatively
brief pioneering history of the Society. I would like to pay
tribute to Tony's achievements, place the apparently
unaccountable event of his departure in context, and clarify
the Science Museum's position.

The origins of the Society are within easy recall. As curator
of computing I paid innumerable site visits in response to
offers of obsolete equipment from potential donors faced with
having to dispose of cherished machines. Visiting these
doomed equipments and engaging with their minders made it
evident that there was expertise, goodwill and enthusiasm that
lacked organised expression. The Computer Conservation Society
was conceived to provide a social and organisational focus for
this community of isolated practitioners who wished to share,
contribute, impart knowledge and skill, or simply participate
in a continuing way in an activity that was meaningful to
them.

I approached the British Computer Society in 1989 to seek
support. The upshot of the appeal was the CCS and the
migration of Tony Sale, then head of the Technical Division at
BCS headquarters, to the Science Museum, the natural
institutional host for such activity.

We should be clear that the part of the context that favoured
so promising a start was the prospect of a major new computer
and telecommunications gallery and the pledges of financial
support for this from a consortium of sponsors. The
restoration activities of the CCS and the funding of Tony's
initial two-year contract were part and parcel of the
Information Age Project (IAP).

The overt justification for incorporating the CCS restoration
activities into the IAP was to deliver working historic
exhibits for this new exhibition. The political realities
were such that without the impetus of the IAP and its
attendant external funding Tony would not have been hired,
however worthy the cause and however powerful the rhetoric. So
the occasion of founding the Society (not the motive, mission
or the need) cannot be separated from the IAP venture.

With the demise of the IAP in 1990/1 - a bitter disappointment
to the whole team - support for a senior full-time post for
computer restoration was always going to be vulnerable. We
prolonged the formal ending of the IAP as long as we could and
then engaged in several months of roller-coaster lobbying the
insecurity of which Tony bore with philosophical fortitude.

Reprieve came in June 1992 when the newly formed Conservation
unit saw the value of the pioneering restoration work already
accomplished. It recognised the advantages of using the work
of the CCS as a model of how to manage complex multi-media
holdings. The Conservation unit funded a one-year pilot
project to capture and consolidate the lessons to be learned
in conservation, archiving and documentation, for application
to other collections. It is a significant tribute to the CCS
that its achievements were viewed in this light by the
conservation unit of a major national museum.

As part of this project hundreds of original circuit diagrams
are being archived on fiche and hard copy, and some 2,500
items of documentation and historic archive material have been
indexed on a database. These services are very substantial and
we are indebted to the Conservation unit for their industry
and support. The cavalry had again arrived in time.
Regrettably, coincident with Tony's departure, it has galloped
off again to other wars and other sieges.

Everyone who has been associated with the activities of the
Society knows at first hand that Tony has been the driving
force behind many of the major initiatives of the Society. His
energy, determination and absolute sense of direction are as
legendary as his incomprehension and intolerance of
unnecessary delay. Tony defined his goals and could not be
deterred or distracted from accomplishing them. His focus and
direction are evident in his gait as anyone who has seen him
purposefully walking down the long passage to and from his
office and navigating his way round the obstacle course of The
Old Canteen will know.

With the support and endorsement of the CCS Committee the
objectives Tony delivered are a testament to his commitment
and to his abilities, strategic, organisational and technical.
He established the Corporate Sponsorship scheme which produces
income to fund many of the Society's activities. The value of
the independence this affords is inestimable.

He established and maintained a programme of seminars which
have become a unique forum for the history of computing; he
assisted in the creation of Resurrection - a distinctive
chronicle of historical activity; as a conscientious recorder
of history he produced the only documentary video records of
the construction of the Babbage engine and developed the
techniques and hardware for indexing video material; he served
and continues to serve as an energetic secretary of the
Society; he championed the cause, sometimes with explosive
pointedness, of indexing our uncatalogued archives of papers;
and to top it all, the activity for which he is perhaps most
visible is the computer restoration programme for which he
marshalled and coordinated the activities of the Working
Parties.

I recall the Director of the Science Museum, Dr Neil Cossons,
thoughtfully observing a Young Engineer of the Year event a
few years ago. He pointed out the bright young kids in DayGlo
tracksuits holding forth excitedly on their inventions and
commented on the contrast between these brightly attired kids
and the unmoved men in dark suits (engineers) that surrounded
them, out of whose mouths dust emerged when they spoke. He
asked what had happened to transform these creative young
individualists into the uniform brigade of otherwise
doubtlessly distinguished seniors.

Tony was himself a young electronics prodigy and his
insatiable inventiveness is very much intact. I offer him to
Dr. Cossons as evidence that at least one of those youngsters
from an earlier generation survived the often deadening
process of professional life.

The Old Canteen, Tony, and the cheerful band that gathers to
beguile old machines into life, are part of a renegade
culture. The relationship of the CCS restoration activities to
the Science Museum is symbolised by the ramshackle Canteen
building in the car park standing alongside, but slightly
separate from, the imposing 'mansion' that is the parental
edifice of the Museum.

When we colonised The Old Canteen for the IAP and the CCS it
had a leaky roof, bad security, and was far from a corporate
des. res. - no pot plants, naff decor and not a flipchart in
sight. While our building was perceived as a decrepit hut we
were left alone, either through the wisdom of benign neglect
or institutional indifference.

In this unprepossessing building we created something of
manifest value to the Museum which then began to absorb the
activities as part of a programme of 'consolidation'.
Institutionalisation offers security. But there is a price:
our hitherto unfettered freedoms to function efficiently and
coherently as we deem fit without the frustrations of a multi-
layered and diffuse bureaucracy are lessened, and the
distinctness of our identity suffers some inevitable blurring.

The Old Canteen is now a prized piece of real estate fought
over by the institutional Titans locked in a territorial
conflict. Where to now without Tony on site and with the
threat of partial eviction?

In recent negotiations the Science Museum has committed to
provide alternative permanent facilities for the continued
activities of the CCS Working Parties. The location of these
facilities is a short drive from South Kensington - Blythe
House, a large fully-warded museum store in Hammersmith shared
by the Science Museum with two other national museums.

Two dedicated rooms have been allocated in the first instance.
One room will accommodate the Elliott 401 and the Elliott 803.
The other will take the DEC equipment (PDP-8s, PDP-12, and
more). These rooms will be fitted with racking and storage and
will provide facilities for the continued activities of the
associated Working Parties.

Restoration activity on the 401 will continue in The Old
Canteen for the meanwhile. The project will continue to enjoy
the valued attentions of the Conservation unit and the high
standards of conservation work they do in preparing the 401
subassemblies for reassembly and recommissioning. Pegasus too
will remain in situ while its fate as an object for public
display is debated.

We will continue to press for facilities to house new
activities - the restoration of visible record machines, a
permanent home for the S100 machines and for the investigation
of recently acquired machines from Russia.

The restoration activities will therefore be split between the
new site and the old. It won't be the same, I know, but we
will have made the important transition from being squatters
in a car park to having a permanent address. The Museum will
continue to provide at no charge lecture hall, meeting room
and seminar facilities to the CCS as a learned professional
society.

These are the agreed commitments the Museum has made to the
Society to date. In allocating permanent facilities the
Museum has demonstrated its recognition and support for the
Society's activities, and very much hopes that the CCS will
continue to take advantage of this and to regard the Science
Museum as its parental home.

Doron Swade is Senior Curator (Computing and Information
Processing) at the Science Museum.

Obituary: John Cooper

Chris Burton

One of the Society's most active members, John Cooper, died
on 13 June after a short illness.

John started his career with a telecommunications course at
Enfield Technical College while apprenticed with Standards
Telephones and Cables, New Southgate. He performed his
National Service with the Royal Air Force, where he was
involved with both telecommunications and radar, and then
joined Northampton College of Advanced Technology (NCAT) in
1959 as one of a small team of computing engineers.

His duties there included maintenance of the College Pegasus,
and later an ICL 1905 and a large analogue computer. In
addition, his design abilities led him to produce Logic Tutors
for the students (long before these were commonplace) and many
sorts of interface electronics for the College departments.

He remained with NCAT through its transition to City
University, taking on support for all the proliferation of
workstations, personal computers and networks - he was skilled
at rapidly assimilating new developments as they appeared.

He decided to retire early from the University two years ago
to carry out freelance work, which included interfacing a
personal computer to the second Babbage Difference Engine in
the Science Museum, to facilitate diagnosis.

John was one of the first members of the Computer Conservation
Society, and his experience and background made him an ideal
first Chairman of the Pegasus Working Party. He ably led the
team in pioneering the methodologies needed to combine
curatorial conservation needs with the desire to restore a
large machine to working order. More recently he was also a
key member of the Elliott 401 Working Party.

His energy, enthusiasm, skills and generosity will very much
be missed. We extend our sympathies to his wife Beryl and sons
Christopher and Simon (all members of our Society) and to his
daughter Serena.

The Problems of Software Conservation

Doron Swade

Computer software is not yet an explicit part of the
custodial mandate of the museum establishment and there
is a growing alarm at the historical implications of this
exclusion. The nature of software is philosophically
problematic. In practical terms, a programme of
acquisition and conservation is technically forbidding as
well as resource-intensive. This article attempts to
locate software as an artefact in the material culture of
museums and explores some of our preconceptions and
expectations for a software conservation programme.

The purpose of this article is to explore museological aspects
of software. The issues raised are concerned less with
computing as an historiographic tool than with computing as an
object of historical study.

Museums are part of an object-centred culture. Their essential
justification is the acquisition, preservation and study of
physical artefacts. Physical objects, their meaning,
significance and their care, dominate a curator's professional
psyche. One of the first tasks, then, is to locate software in
the artefactual landscape.

Software, a term in general use by the early 1960s, is usually
defined negatively: that is to say, a component of computer
systems distinct from hardware. The Oxford Dictionary of
Computing (1986) defines software as 'a generic term for those
components of a computer system that are intangible rather
than physical'.

The Science Museum's Corporate Plan for 1992-1997 states that
one of its 'core objectives' is to 'acquire the most
significant objects as physical evidence of science
worldwide'. We have a conflict. If what distinguishes software
is something non-physical, and software is in some sense
irreducibly abstract, then it falls outside the mandate of
material culture and a conscientious museum curator might have
qualms about mobilising resources to acquire and preserve it.

The dilemma may seem pedantic. But there is a real issue: in
whose custodial territory does software fall? Is it the
responsibility of the archivist, librarian, or museum curator?
For unless existing custodial protection can be extended to
include software, the first step towards systematic
acquisition will have faltered, and a justification for
special provision will need to be articulated ab initio in
much the same way as film and sound archives emerged as
distinct organisational entities outside the object-centred
museum establishment.

The distinction between hardware and software is not absolute.
'Firmware' (programs held in ROM) defies categorisation as
exclusively one or the other. The ROM-chip itself clearly
belongs to the universe of hardware. Yet insofar as the chip
embodies a symbolic record of a program it is apparently also
software. If forced to answer the question 'is firmware
hardware or software?', you could be excused for responding
with a helpless 'yes'.

One way of bypassing philosophical misgivings about the
materiality of software is to appeal to the broader mandate of
science museums to maintain a material record of technological
change. Software represents a substantial human endeavour, and
the intellectual, economic and material resources involved in
its production and distribution represent a major
technological movement. Its importance is not in dispute. So
perhaps we can bluff it out and collect software by day
leaving philosophical disquiet to the troubled night.

In practical curatorial terms the abstraction of software is,
in any event, something of a pseudo-problem. We do not collect
prime numbers or polynomials. We collect instead physical
models, mathematical instruments and the written deliberations
of mathematicians. In much the same way our curatorial concern
for software centres on the external physical record of
programs and data - coding sheets, punched paper tape, punched
cards, flowcharts, manuals, magnetic discs, publicity
literature i.e. the distinct physical media of representation
and storage.

So we could perhaps make a case for offering curatorial
protection to artefactual software by regarding it as part of
the contextual and functional extension of hardware without
which technical history would be incomplete.

But the lump under the carpet is still visible. Once we grant
ourselves the licence to collect the physical artefacts of
software, there remain respects in which software is both
like, and unlike, traditional museum objects.

At the centre of curatorial practice is something called an
inventory procedure. This procedure formally transfers the
'title' of the object from the donor/lender/vendor to the
Museum. Each inventoried object is the direct responsibility
of a named curator, the collecting officer, who signs a formal
declaration of responsibility for each object when it is
acquired. "I hereby take responsibility for the objects
described overleaf" is the forbidding form.

An object once inventoried is subject to formidable safeguards
against disposal and unqualified alteration. In museum culture
the physical integrity of an inventoried object is sacrosanct
and the act of inventorying marks its transition into
protective custody.

Objects decay despite our best efforts to conserve them.
Nonetheless, when we acquire a brass telescope it remains a
brass telescope despite inevitable deterioration. We refer to
a rusted telescope as a 'rusted telescope' or more
impressively, 'telescope, condition poor'. The time-scale of
its degeneration does not seem to threaten its identity as a
telescope: that is to say, its physical deterioration is
sufficiently slow to support the illusion of permanence. That
it is a telescope seems not to be at risk.

Ultimately when time reduces our prized telescope to some
orphaned lenses adrift in a little heap of metallic oxide we
sadly shake our heads over the debris and say 'this was a
telescope', or, in Pythonesque terms, 'this is an ex-
telescope'.

So armed, I am now resolved to inventory some software for the
computer collection. I take from the cupboard, where it has
lain in limbo, the boxed mint-condition version of Windows 1.0
that a kind donor sent me. My hand is poised to sign the
ominous declaration of responsibility.

The manuals and the box are unproblematic. It's the thought of
the nine floppy discs that furrows the brow and stays the
hand. In what sense can I responsibly sign when I know full
well that within a few years there is no guarantee that the
disc will be readable?

Posterity stretches ahead of us without limit in time whereas
disc manufacturers, when they are prepared to commit at all,
are reluctant to do so for more than a few years. (Banks were
advised in the US in the early eighties that no archived
magnetic medium over three years old should be regarded as
reliable).

At a practical level, to commit to preserving a functioning
Windows 1.0 package is to commit to an active programme of
periodic renewal by copying to fresh stock, or transfer to a
less impermanent medium. A programme of renewal or transfer
requires new resources and, more significantly, implies the
provision at some time of operational contemporary hardware or
a functional equivalent. Neither requirement is trivial.

But is the Windows disc like the telescope with an identity
that transcends its state of repair? If what makes it a
Windows disc is the information content represented by
magnetic configuration of the disc coating then does 'Windows
1.0, condition poor' mean anything? Does meaningful collection
of software imply a functionally intact copy with the promise
or potential of running it? We do not ask this of the
telescope. 'Telescope, broken' does the job.

We can perhaps draw a useful analogy with pharmaceutical
products. I learn from my medical sciences colleagues that the
Science Museum has recently placed some proprietary drugs on
inventory. Panadol, say, is now an inventoried object.

There is valuable cultural information in the physical
artefact: tablet form, bubble-pack press-through dispenser,
advertising imagery used in the logo and packaging and
information about consumer appeal. But we can be pretty sure
that the drug company will not guarantee the potency of the
sample beyond its sell-by date.

We are clearly acquiring Panadol at least partly as a cultural
artefact on the understanding that its chemical infrastructure
and therefore its potency is ephemeral. In museological terms
Panadol does not cease to be Panadol when it is no longer
chemically potent. Similarly, the centuries-old 'poison-tipped
arrow' remains so-called though the likelihood of any residual
toxin is remote.

Is the Windows disc like Panadol? There are strong
similarities. 'Potency' in both cases is not visually
meaningful. Function is not manifest in external form.

Further, the Windows discs are no less a vehicle for
contextual and technical messages than the Panadol pack:
symbolism and imagery in brand logos and packaging, quality of
label print, physical size, soft or hard sectored, whether
factory write-protected, presence of reinforcing ring and so
on. The discs are informative as generic objects (media) as
well as conveying product-specific information about Windows.

So why the nagging need for functional intactness in software?
Does 'functional intactness' make especially exacting demands
on preservation practice?

Software we know is 'brittle'. It degrades ungracefully. We
are all familiar with the awful consequences of what in
information terms may be a trivially small corruption. One bit
wrong and the system crashes.

There are however situations in which the value of
magnetically stored information is not bit-critical. Discs
used as storage media for textual data as distinct from
programs provide one example. A progressively corrupt magnetic
record is usable nonetheless. The residual data is not
deprived of meaning or access by partial corruption.

The 'all or nothing' fears do not in this case apply and we
may be encouraged to re-examine whether there is some give in
the apparently uncompromising need for bit-perfect records of
program software.

If we look at the effects of corruption on program performance
we can identify three broad categories. Non-critical
corruption covers situations in which unused portions of the
program are compromised - unused print drivers, irrelevant
utilities or subroutines, for example.

With a steam engine, say, 'non-critical corruption' would
correspond to the damage to an unused or non-critical part - a
nut dropping off, a dented panel. Damage in this case does not
compromise the primary function, that of producing traction.

Critical corruption leading to evident malfunction is a second
category - the system hangs, the cursor freezes, the
operating system fails to boot, or the program produces
obvious gibberish. In our steam locomotive comparison, the
engine loses traction, or makes an expensive noise and stops.
So far the comparison with physical machines works.

The third and most worrying category is critical corruption
that produces non-evident errors - a maths program that
produces an incorrect numerical result, a database manager
that cross-labels data records, for example.

Comparison with the stalled steam engine is not obvious.
Perhaps a closer analogy would be with a telescope that
misrepresented what we were looking at. The distant unsighted
object is a church steeple. But observed through our telescope
(condition, good) we see the image of a mosque. It seems
reasonable to conclude that if archived program-software is to
be run, the need for bit-perfect records is uncompromising.

Once we accept the need for functional intactness in archived
program software we are seemingly committed to the indefinite
maintenance of bit-perfect records. Engineering instinct
favours retaining the medium and format of issue to ensure
compatibility with the original hardware.

If the medium of issue is magnetic then we are committing to
an active program of periodic copying and integrity checking.
Transferring software to a more permanent storage medium
(optical disc for example) offers a tempting liberation from
the fate of perpetual renewal.

Correct operation of applications software relies more often
than not on particular revisions of system software, program
patches, hardware upgrades, firmware revisions and machine
dependent interfacing to peripherals.

Transferring to an alternative medium requires new data
formats yet to be standardised and dependence on a new
generation of hardware to read or download stored information.
Interfacing to these devices and executing code so stored is
not straightforward. Transfer to a more permanent medium is
not without penalty despite its promise of releasing Sisyphus
from his fate in the copying room.

An implicit tenet of museum life is that the original object
is the ultimate historical source. Part of the justification
for preserving original objects is they can be interrogated in
an open-ended way in the light of unforeseen enquiry. A
meaningful software preservation program therefore implies the
availability of operational hardware.

In 1989 the Science Museum, with the British Computer Society,
founded the Computer Conservation Society. The Society has had
signal success in restoring to working order a Ferranti
Pegasus, a large vacuum-tube machine dating from 1958, and an
Elliott 803, a discrete component germanium transistor machine
dating from 1963.

At best such ventures can extend the operational life of
obsolete systems. But however successful these endeavours, we
have to accept the eventual demise of such systems. The fact
of the matter is that in archaeological terms the operational
continuity of contemporary hardware cannot be assured.

What meaning, then, does an archive of bit-perfect program
software have if the material cannot be run? One way forward
presently being explored by the Society is to simulate early
hardware on present-generation computers using the restored
original as a benchmark. Two simulations are well advanced,
one for the Pegasus, the other for a German Enigma cypher
machine.

In the case of the Pegasus, console switches, console
oscilloscope traces, input/output peripherals (paper tape,
teletype-style printers) are visually simulated and animated
on-screen. The operator can write, run and debug programs by
'driving' the simulated controls and the simulator responds
appropriately even to the extent of execution times.

The museological implications of such simulations are
intriguing. In museum culture the original artefact is
venerated at the expense of a replica, duplicate,
reconstruction, or hologram. As mentioned earlier this derives
partly from the possibilities the original offers for open-
ended analysis.

Physical replicas can only incorporate features and
characteristics perceived to be significant at the time of
replication. If we wished to test a new theory about
Napoleon's allergy to snuff, say, it would not make sense to
examine look-alikes of Napoleon's clothing. Prior to the
snuff-allergy hypothesis, snuff-content would not be a
consideration in the making of a garment replicas. Only the
original artefact with authenticated provenance would suffice
for this forensic purpose.

However, logical replication as distinct from physical
replication seems to offer more. Capturing the operational
persona of an early machine on a later machine promises
possibilities for open-ended analysis of the kind formerly
offered only by a working original. The resources to develop
such simulations are substantial and the skills-levels high.
But the technique offers a form of logical immortality as
computer languages used for the simulations become
increasingly machine-independent.

I have touched briefly and perhaps unsystematically on a few
of the issues agitating concern in the curatorial world. The
task of developing an interpretative framework in which to
locate and debate the nature of information and the role of
information processing machines is substantial. The technical
and resource implications are formidable. We have a long way
to go.

Doron Swade is Senior Curator (Computing and Information
Processing) at the Science Museum. His article is based
on a paper presented at the Society's seminar held at
the Museum on 25 June 1992. The original title of the
paper was "Collecting Software: Preserving Information
in an Object-centred Culture (do we inventory the
floppy?)". The paper has previously been published in
History and Computing Vol 4 No 3, 1992.

Editor's note: History and Computing is the journal of the
Association for History and Computing. This is an
international organisation which aims to promote and develop
interest in the use of computers in all types of historical
study at every level, in both teaching and research. Founded
in 1987, its membership consists principally of member
associations, though individual membership is also possible.
Readers wishing to know more should contact me.

George Alfred Julius and his Automatic Totalisator

Charles Norrie

The problems of uncertainty had a fascination for the early
pioneers of computing, especially making sense or order out of
uncertainty. Babbage was interested in life assurance and in
game theory. Turing had a wide variety of interests, including
game theory, gambling systems, poker and statistics.

I want to discuss George Alfred Julius, another pioneer who
built a system to deal with uncertainty - his automatic
totalisator. This talk mainly covers the totalisator as it was
at Haringey.

A totalisator is a machine to process the results of a type of
bet known as pari mutuel. This is a bet between bettors, and
not against a bookmaker, so it acquired the name pari mutuel,
meaning bets between ourselves. The payout is calculated by
dividing the total pool of stakes, less deductions for tax and
the operator's overheads, between the backers of the winning
dog, or competitor (the machine could be used for other types
of betting such as horse race betting).

There are many sorts of totalisator bet, and there is a series
of rules for determining who are the winners and how they
should divide the pool.

One aspect of the tote bet is that the ticket issued does not
need to say what the payout will be if the bettor's choice
wins. It is an entitlement to be paid out at a rate depending
on the monies taken before the race starts. Fixed odds are
avoided; you don't have to record and process the value of the
odds offered when the ticket is sold.

The totalisator originated in South Australia. The South
Australian racing community became increasingly irritated with
corrupt bookmaking practices. Holding that most robust of
Australian investigative devices, a Royal Commission, they
proposed to adopt the pari mutuel betting system as used in
France.

So a bill was introduced in 1879 into the South Australian
legislative council to legalise the tote and curb the
"welshing" and corrupt bookmaking. It was strenuously opposed
by religious groups lobbying on the grounds that it would
promote betting rather than regulating it, and they were to be
proved correct.

The legislation made it onto the books by one vote. This
success provoked a reaction, and the tote was closed down
three years later, only to be revived for the 1888 season.

Tote machines existed before Julius. Eckberg patented a
mechanical totalisator in 1879 at the height of the early
Australian interest in the tote. Another Australian, Gabriel,
had a system which used the counting of marbles, or possibly
steel balls, as a method of calculation.

These two systems were not automatic. "Automatic" in this
sense means achieving an automatic recording and summing of
the bet made by an investor, and printing and issuing of the
ticket.

The automatic totalisator, in the sense that Julius used the
term, was not used to compute the payout of the winners. This
was a manual task at Haringey, performed after the race by two
clerks and an accountant. Modern systems do of course perform
this last stage automatically.

George Alfred Julius, engineer, was born in 1873 and died in
1946 in Sydney, Australia. His father was a Christian
socialist with a bent for engineering. One anecdote has the
father as a curate in a poor parish, unable to raise money to
mend the turret clock, taking it apart, boiling the parts in
oil and putting it back together again.

The family moved to Ballarat, Victoria in 1884 when George was
11. Here his father was vicar of St Peters, a go-ahead mining
town. It's tempting to suggest that Julius would have become
aware here of the unregulated betting he was to do so much to
reform. Victoria at this time, unlike South Australia, had not
tried tote betting. Historians believe many of the bookmakers
were corrupt.

In 1899 Julius's father became bishop of Christchurch, New
Zealand, a settlement founded on Anglican principles. Here
Julius came in contact with a man who was to have a decisive
effect upon his life, CY O'Connor. Also from an Anglo-Irish
background, O'Connor belonged to that essential breed of
individual of the Empire - the government engineer.

O'Connor subsequently sought a post in Western Australia as
Government engineer there. He worked on the port of Freemantle
for exports, railways to develop the State, especially its
valuable timber resources, and the water pipeline for the
recently discovered Kalgoorlie gold field. Julius on
graduation was recruited by O'Connor to the railway workshops
at a premium salary.

Julius became an instructor at the technical institute. He
wrote a standard work on Australian hardwoods there, a vital
exercise in developing the State's economy. Subsequently he
quit government service and moved to Sydney to form his own
engineering partnership, Julius, Poole and Gibson.

His initial reason for coming to Sydney seems to have been a
project to investigate problems with the defective electrical
and mechanical installation of the Sydney power and lighting
scheme. The totalisator was a minor aspect of a very busy
business engineering and political life.

Anecdotal evidence from Julius' son Aubrey, who was the one
son to go into Julius Poole Gibson, suggests that though the
totalisator was a separate venture from Julius' engineering
consultancy, the latter benefited from the orders for
buildings at racecourses. Julius' firm's order book suggests
also that this was so.

It was while he was in Western Australia that Julius began to
patent devices for his totalisator. It's clear even from the
first patent that Julius had grasped an important principle of
betting, simultaneous demand - people wishing to bet at
exactly the same time. Hence in choosing areas for monitoring
the sales application of his machine he proposed applications
that would have a similar kind of simultaneous demand.

Voting was one. Another was sales in a department store: as
sales happened individual departments would ring up the sales
and there would be a grand total for all the sales across all
the departments in the store at the same time. In this he
anticipated computerised in-store stock management systems
that began to be only feasible in recent years.

And why Julius? Julius' church background does not suggest a
milieu particularly conducive to betting or totalisators.
There is no evidence that Julius was interested in betting
himself; several anecdotes suggest that he never betted at
all, but he did marry into a family well known for their
support for the turf. CY O'Connor possessed a number of
racehorses which "invariably wore Irish colours".

One anecdote recounts that when the Ellersley tote, which was
the first to be opened in Auckland, his father, who was then
archbishop of New Zealand, asked to be shown over it by his
son. To preserve a certain distance of the church from the
tote it was arranged that the archbishop would tour the
machine on the morning before the first race. However so
engrossed did the old man become that he only emerged while
the public was being admitted to the afternoon's racing. This
led to a wide and entirely unfounded speculation that the
archbishop, not the engineer, had been responsible for
inventing the machine.

Haringey was one of the early stadiums to be equipped with a
Julius totalisator, taking advantage of the Amended Betting
Houses Act. Presumably the Government regarded it as a way of
generating revenue. The Chancellor of the Exchequer, Winston
Churchill, had no particular respect for greyhound racing,
describing it as animated roulette.

The Haringey machine was a typical Julius product,
representing about 15 years of development and improvement.
Taking the elements in chronological order as shown by the
patents, the Julius totalisator was a progressive improvement
from that earliest 1913 model in Ellersley. That machine was
simply mechanical.

The Haringey machine was probably constructed in Australia.
There is some indication that Julius was constructing machines
for the English market. Later he was actually to set up in
this country.

Haringey Stadium was on Green Lanes, just north of Manor House
station in north London. It was closed in 1987, a victim of
the extended twilight of greyhound racing caused by the growth
of other leisure opportunities, and also rising land values
which made attractive alternative site uses. Today Haringey is
famous for its supermarket and there's no sign of a dog track
left.

Ironically it was the decline of dog racing that preserved the
Haringey totalisator. Had the track had a long term viability
the machine would have been upgraded in line with apparatus at
other greyhound stadia.

It should be stressed that the Haringey totalisator isn't in
any sense a one-off. The machines were widely used throughout
Australia and America, where they were known as the Australian
Tote, the British Empire, and even France.

Relatively speaking they do not appear to have been expensive;
there was not the capital available. The Haringey stadium was
constructed on the Haringey dumps - waste left over from the
construction of the Piccadilly Line. Greyhound racing, though
it tried hard to emulate the styles and form of horse racing,
was no such thing. This was betting on the cheap.

Though Julius negotiated with a syndicate for their
introduction on the racecourses of England he was not
successful, as the Jockey Club would not permit the Tote.
Nevertheless they relented to the extent of permitting the
Automatic Telephone Company of Liverpool to build one at a
cost of £2 million in the 1930s. A Julius machine would have
cost mere thousands. A tote in England seems to be a
particularly low cost operation, though other machines appear
in elegant and stylish buildings.

Before I return to the Haringey totalisator I'd like to spend
a few minutes talking about the background to it.

Because tote betting only gives bettors a starting price
there's no incentive to bet early. Indeed there's a
considerable disincentive; as betting proceeds bettors get a
steadily clearer indication of the sort of price or odds they
will end up with.

The ideal is to make the last bet before the traps are open,
when of course betting must cease, in the full knowledge of
the odds available from the previous bets.

As all bettors want to do this the demand for bets rises as
the time of the race draws near, and the flow of bets becomes
faster and faster. (Contrast this with fixed price odds where
the decision to bet early is sometimes made in the light of an
attempted objective assessment of a dog's probablity of
winning.) It's certainly in the tote operator's interest to
service this demand as efficiently as possible for his return
is a fixed proportion of the total stake.

Julius seems to have had some doubts at an early stage about
an electrical installation, and he did not use electricity
until he had devised a suitable means of ensuring that a
ticket couldn't be issued unless there was a positive
registration of the bet that had been made at the same time.

The next bit to go on to is the need for simultaneous betting.
The only alternative even in 1920 was the marble system that
Gabriel had invented. It was used to drive accumulators, a
display drum and an odds machine.

In its original conception as it must have been at Ellersley,
the totalisator consisted of direct action ticket machines
that mechanically drove an epicyclic mechanism attached to a
drum (used for displaying the results). Its arrangement of
ratchet wheels, relays and bevel gearing was arranged about a
common axis. The operation of a relay permitted a ratchet to
turn one position: as a result the axis of the epicyclic chain
would turn, usually by one eighth of a complete rotation, to
enter one bet. Higher priced bets could be operated by
allowing a bigger gap between the ratchets, or by using a
different barrel with a different value attached to it.

The rotations were transmitted by bevel gears through the
adjacent ratchets, which were all on the common chain. Hence
ratchet and bevel gear mechanism had a double function; the
bevel gears would rotate when ratchet is operated but they
could also transmit motion independently.

Each epicyclic chain could be attached to about six ticket
machines. In theory you could have 10 or 20 ticket machines
attached to it, but we're looking at machines in which there
were usually four to six relays attached to the epicyclic
gear.

This early purely mechanical system couldn't meet the speed
needs of tote betting, so he had to turn to electricity. One
problem was the stopping and starting of the epicyclic chain
with many machines attached to it. Various claims are made for
the size of the machines eventually created; the one at Champs
Elysees is said to have served 600 ticket sellers. Haringey
had 150, and there was space for 240.

There was another deficiency with the Ellersley machine. While
the machine accurately recorded bets, the ticket seller was
still obliged to select the appropriate ticket for the
customer. This permitted error, and fraud in the worst cases.
Julius therefore began to look at ticketting machines that
simultaneously registered the bet and printed the ticket. This
does not seem to have been successfully achieved until 1918 or
later.

The Haringey machine covered three types of bets for only six
dogs (contrast that with over 42 horses at Randwick in
Australia). There were Win, Place and Forecast bets. Later
totes may have handled quinnella, duella, triplex and the
other complex bits loved of the betting community.

One can see that there is a disadvantage in a hardwired system
because if you want to increase the number of dogs in a race
or introduce a new bet, you've got to get a new machine. It's
not programmable in any sense whatever.

Julius realised that electrical operation would permit much
higher speed than mechanical. Ticket sellers might be able to
sell at 100 per minute but electromagnetics would register 10,
possibly 50 times this. Hence rather than having each ticket
driving a single relay with the resultant long epicyclic
chains - mechanical devices which needed to stop and start
with consequential inertial problems - he used a rotating
selector associated with a group of ticket machines.

I should be careful in describing this as time sharing;
Julius identified its advantage over its competitors as
saving equipment, not sharing time on an expensive machine.
It was necessary to drive two separate relays for each
machine, one on the grand total machine, one on the
individual dog machine. In the original Ellersley machine
the ticket machine would have driven a counter - a big drum
device that could be read from anywhere on the course. These
had to be large, 2 feet to 18 inches across. These drums are
important because they are the only legal output device
required by law.

Haringey had two sets of drums in its time. The original drums
had three wheels, but they were disconnected and just put to
one side. The new drums had four wheels, five in the case of
the grand total drum.

But now Julius had been caught up in the success of his
machinery again. Hundreds or thousands of bets a minute put a
severe stress on drum moving mechanisms. They were big things
- 2 feet across - and stopping them in relation to betting was
difficult. The electrical system which controlled the opening
of the traps and starting the race also signalled the end of
betting, and it was activated with the throw of a single
switch. It disabled all the ticket machines simultaneously;
they had to come to a dead halt.

So Julius had to solve this problem of the inertia. It was
legally necessary to retain the drums, but was it really
necessary to show the most quickly moving drum? No, thought
Julius, they can be disconnected because if they are moving
quickly they can't really be read. But if you disconnect them
the addition has got to be done somewhere else; and this is
where they had to use the tables.

Julius decided that, rather than feeding the rotor output to
the epicyclic train to a drum which had to stop and start as
needed, he would feed it into a storage system, and then
process output at a steady rate. The storage mechanism would
have a lower inertia than the drums, and the steady unloading
of the bets would cope with the severe changes in demand at
the start of the race. Of course in the process you get a bit
behind where the betting has currently reached, but never
mind.

So the bets wind up a spring in a barrel and unload it at the
other end. Then you can deliver the output in a number of
ways: onto drums, or onto other barrels. We could in fact have
many barrels to distribute the output over many machines,
rather than have one that you're putting a lot of stress on,
and distribute the addition. This keeps the number of
epicyclic chains small and one gets to a setup with a series
of drums side by side built up into a table. So we've got a
whole series of relays at the top where ticket machines are
coming in through their commutators and the betting
information is being unloaded at our end. With that you can
drive the rest of the equipment smoothly and efficiently.

The display drums really indicate in some way the state of the
accumulator table a little behind time. Could this be
described as a mechanical buffer? It's not quite the same as
a computer buffer because it's not LIFO or FIFO.

When betting has finished you have got units which haven't
been recorded, so they must be transferred automatically
through to the drums. Then when you've finished with the race
you've got to unload the bets and reset it, and for that we
have a man - it's not done automatically. This is one of the
major problems of the Haringey machine; you needed to have a
team of six people just to reset these things 10 times a
night.

We haven't got a lot of information out that's useful to a
punter - all we've got is counts of the number of bets. As the
size of the Julius installation grew, there was a problem with
informing bettors in an effective manner. There seems to have
been only one set of display drums per installation: as the
size of meetings grew Julius could do bigger racetracks, and
it could be difficult to read them. Scaling up the size of the
drums was impossible because of their inertia problem.

Again, assessing betting prospects by estimating the ratio of
moneys invested in different competitors was not user friendly
to the average investor. Julius' search for a solution to this
question took considerable time to come to fruition as a
workable apparatus. His earliest patent expressed some
interest in the idea of comparison between different totals,
while a paper dated 1920 on aids to calculation described in
detail several ratio calculating devices.

I can't find that he thought of taking instantaneous snapshots
and then doing a mechanical computation, but he did come up
with an odds machine. He was later to say that he devised
this when he came to England in 1928, and encountered British
investors who regarded with consternation the lack of odds
which the tote gave them compared with the fixed odds machine.
Perhaps one reason for the introduction of odds equipment was
to encourage people to migrate to the tote; perhaps we should
regard this as an early system emulation.

This article is an edited version of the talk given by the
author to the Society at the Science Museum on 25 March 1993.

The design of Pegasus

Ian Merry

I'm uncertain whether I welcome this opportunity to celebrate
the engineering genius of Charles Owen and the conceptual
brilliance of Christopher Strachey, or whether, like pious
Aeneas before Queen Dido of Carthage, I've been asked to
awaken ancient and unutterable feelings of regret. Regret that
following the outstandingly successful development of Pegasus
the design team was disbanded and, at least to my way of
thinking, no worthy successor has ever been developed in
Britain.

I'll identify a few of the individual characteristics of the
members of the design team which had a significant influence
on the design.

I learnt from my experience with Pegasus that good design
requires the prejudices of a single design authority to be
both articulated and respected. Problem definition is a vital
precursor to problem solution.

Successful design depends on solutions with designabilty,
amenable to design analysis and calculation, since design is
constrained by the limitations of materials. Successful design
goes, so to speak, with the grain. These were in effect the
precepts on which both Owen and Strachey based their work;
they were not however very typical of the world of electronics
in the 1950s.

What was this world like? The impact of radar development
during World War Two was still much in evidence. A major
advance in glass technology, dating from about 1938 with the
appearance of the Philips EF50 valve, had fostered a
succession of high-gain miniature vacuum tubes only about an
inch in diameter and no more than a few inches in length.

Point contact germanium diodes had been developed during the
war as radar demodulators, based on little more than the
kitchen science of crystal wireless sets of the 1920s. With
the inventio n of Schockley's point contact transistor in 1947
a hesitant semiconductor industry had arisen concentrating on
germanium semiconductor technology, hampered by the
variability of point contact devices, and only marginally
familiar with the technology of silicon and junction devices
on which we all now depend.

Electronics was still mainly the concern of telecommunications
and broadcasting, the former with its 22 inch wide racks of
equipment 6-8 feet high, and the latter with racks as wide as
24 inches (at least in the BBC), bearing monolithic cadmium
plated steel chassis, each weighing tens of pounds with a
dozen or more valves and associated circuits.

Significantly, most of those involved in the wartime radar
development had been graduates in physics, without academic
engineering backgrounds, since in Britain at least electronic
engineering was widely regarded as a dilettante not to say
insecure profession until well into the 1950s.

This circumstance together with wartime pressures had confused
the concept of design with the narrower field of circuit
design, and established a widespread design tradition of suck-
it-and-see whenever a problem arose outside the immediate
experience of the designer. That's not to say that suck-it-
and-see was how circuits were designed; that depended entirely
othe intellectual probity of the designer. But suck-it-and-
see was still very much the way of dealing with any problem
that was not immediately in the competence of electronics.

Again, where the logical power of electronic digital
computation had been clear since the early 1940s to the
indoctrinated of Bletchley Park, it was the domain of the
smallish band of mainly academic successors, among whom few
had studied design as an engineer.

Even where, as in the BBC Engineering Department, numerically
based design was given its full due, on the electronic front
this was in the context of high quality analogue circuits made
linear with a quasi-statuary 40 db of negative feedback!

Consequently there was no pressure at all on the makers of
valves or semiconductor devices to publish the variances of
their device parameter data. On the contrary it was rarely
clear whether published data represented design targets or
achieved median values!

Lastly, despite the marketing hype of the Festival of Britain
in 1951 and the governmental initiative of NRDC, there was no
longer the recognition of engineering as an important aspect
of the British Raj, as had existed in the 19th and early 20th
centuries.

Turning now to the major players in the design of Pegasus,
there were four in number: Charles Owen, Christopher Strachey,
Brian Maudesley and myself. I would like to pay tribute to
Owen's engineering sagacity.

He had the essential vision of a successful engineer, which is
to have formed an architectural concept of the finished work
from the earliest possible moment. Changes to that concept
could be made as the design progressed, but any change had to
be demonstrably beneficial, and to meet Charles' exacting
standards of acceptability.

Given the clear benefits and the conformity with the standards
of acceptability, there was in my experience no need for
further persuasion. It was stimulating to work with someone
who had no need to reinforce his prejudices with anything but
logic and good sense.

In addition Charles was very ready to pass on his own
knowledge - a characteristic which endeared him to me as I had
no previous experience of digital techniques. With all of
that, and though often doggishly witty, Charles was
essentially a plain man for whom facts were facts and fancies
were fancies.

Christopher Strachey on the other hand was a modern
Renaissance man. Besides his achievements as a mathematical
logician and systems conceptualiser, he was a most talented
musician; he and I used to sing and play together. His skill
in technical discussion or general conversation was such as to
make everyone else present perform beyond their usual level,
as a consequence of his own rather competitive verbal
brilliance.

The third principal member of the design team, Brian
Maudesley, was unusual in both background and personality. A
mechanical engineer from Ferranti Edinburgh fallen among
intellectuals, he held his own in consequence of a unique
capacity for mechanical innovation, and for his mild manner,
all supported by a physical stature of 6' 8".

As for myself, I joined Ferranti after four and a half years
in the BBC Engineering Research Department where I had worked
on a number of electronic and electromechanical projects
connected with both disc and magnetic recording, and where I
had encountered many of the problems which were still then at
issue in the Pegasus project.

My only previous experience with digital circuits had involved
telephone relays - a brief encounter which left me with no
yearning for further involvement with relay switching!

We come now to the principles on which the architecture and
design of Pegasus was based. Strachey's major objective was to
reduce the labour of the programmer, especially by providing
efficient and consistent order code; by freeing the programmer
from undue concern with machine architecture; by minimising
performance bottlenecks; and by maintaining an autonomous
invigilation of all machine functions, using odd-parity
checking throughout.

Owen for his part had an intense preoccupation with machine
reliability and availability. His experience led him to
believe that while this required conservative design, with
care this did not get in the way of elegance and economy. Both
he and Strachey aimed to build all of the complex control
functions without recourse to special purpose circuits.

With both prudence and modesty Owen took the view that basic
circuit elements used in the Elliott 401 represented the
soundest basis for progress. Packages containing several OR
configurations of point contact diode AND gates, logically
ORed, followed by a cathode follower direct output or an
inverter or a simple pulse amplifier retiming and delay
circuit furnished the logical armoury of the bit-level logic,
as in the 401, while single word packages using a nickel delay
line as a serial storage medium provided immediate access
memory for accumulators and registers.

Now it's fairly obvious that the more complex a logical
function, the more numerous are likely to be the various
inputs. So the number of inputs to individual AND gates should
be as little restricted by circuit component deficiencies as
is prudent.

To upgrade the Elliott logic circuits, Owen instituted a
statistical analysis of the problem, and ascertained by
experiment the variance of the germanium diode back leakage
resistance. In this way he avoided on the one hand the Scylla
of AND gates with the more leaky diodes exhibiting pattern
sensitive failings, and on the other the Charybdis of
oversensitive gate design.

In considering the remarkable success in achieving the design
objectives, remember that Pegasus is a serial machine in which
the 39 working bits of each word arrive sequentially at any
point, or as we now say at every interface in the machine.

To maintain the economic advantages of this serial approach,
interface width has to be kept to a minimum, nearly always
only one bit wide. The parts of the machine where static
registers hold a number of words concurrently are thus few in
number.

The thinking required in the logical design, particularly of
the control functions, therefore required the designer to
envisage successive machine states represented by circuit
states changing autonomously and quickly under the inexorable
flow of serial data. This is a duality which it is difficult
to represent conspicuously in any diagram form, and was quite
beyond the descriptive mathematical techniques of the time.

In this regard I well remember the seminar when the logical
designers first gave an explanation of the control
architecture. By then Pegasus was in active use and the
logical design seemed to be consistent, but for my part at
least the description of the various control cycles was and
remains baffling.

Coming now to the engineering problems which had to be solved,
we can regard them arising against three design aims. These
are reliability, economy and performance.

Past experience had shown that the major areas of transient
unreliabilty were pattern sensitivity of individual logic or
storage units, where correct operation continues until a
particular sequence of binary digits occurs which evokes an
incorrect output.

Secondly, on drum systems generally, think of a difficulty and
they appear to have it. Thirdly we had to live with package,
plug and socket electrical contact variability. Happily by
this time other electrical component deficiencies did not
present causes of transient problems, and were adequate in
terms of operational life given that they were not sourced
from suspect quarters such as Government surplus - a false
economy which bedevilled some other projects.

Now except to a mechanical engineer of particular discernment
there is little intellectual stimulus in addressing the
problem of erratic plug and socket behaviour, which is why, I
think, the problem hung around for so long. In many ways this
was the most dangerous of the package circuit problems since
so many package interfaces were at risk.

Maudesley tackled and solved the problem with determination.
To keep the contact resistance of each contact adequately low,
he insisted that it was insufficient to rely on the
comparative incorruptibilty of noble metal surfaces; instead,
on each insertion of a package every female contact should
scrape its corresponding male and ensure a new metal to metal
interface. Given an adequate thickness of noble metal plating
of the male contacts, a quite adequate if limited number of
insertions could be made.

It might have seemed a risky way of proceeding, as noble metal
surfaces can get worn away very quickly. In fact we reckoned
that we could do at least 50 insertions without trouble, and
that was well beyond the number of insertions one would
normally expect a package to receive.

The in-line multi-contact socket used was to have the
necessary female geometry, and a concomitant to this solution
was the provision of a robust and stable mounting for package
board and socket. This was achieved most economically by the
use of aluminium alloy diecastings for the package shelf
mounting.

The robust behaviour of Pegasus after switch-on and throughout
the life of the various machines has been very largely due to
this solution to package structure and contact geometry.

Lastly of course the package board itself had to be of an
adequate rigidity and stability. Attention to details of this
sort had not distinguished previous computer projects.

The drum system appeared to present problems in every possible
area. The geometry of the magnetic fields caused the head
signal to be rapidly attenuated with an increase in the read
head-to-recording medium gap. About half the signal is lost in
geometrical progression for each extra tenth of a bit length
gap.

With a drum diameter of 10 inches and 128 42-bit words per
track, it turns out that an overall variation in signal of 2:1
ensues if the radial runout of the drum surface (due to
machining tolerance, variations in coating thickness and
bearing shake) is no more than about half a thou, and
exponentially pro rata.

Owen had already decided this was too demanding by a factor of
two. He had laid down that alternate bits would be recorded in
pairs of tracks, so that we could have double the wavelength
for each bit, with write and read head diplexing handled by
machine logic. This was a strategy previously adopted at
Elliotts.

I soon realised that not only the diplexing but also the
actual phase encoded waveform could now come directly from the
logic. This removed the need for a special purpose circuit,
pleasing everybody especially me.

However even a total runout tolerance of half a thou appeared
to have caused difficulties with previous bearing design and
bearing life. And there was some disquiet in connection with
the drum under development at Ferranti in Manchester for the
forthcoming Mercury computer.

At the BBC, while studying the problems of television magnetic
recording, I had tackled the problem in the lab by using a
horizontally mounted narrow drum or disc with a little known
360 degree bearing design. This had however to be hand lapped
to a radial consistency of about one tenth of a thou. The drum
coating with its magnetic surface was then sapphire turned.

A 360 degree bearing is nominally permanently lubricated, and
it works best with a lubricant with particular physical
properties like sperm oil. I introduced this with an eye
dropper to my own machines. Maudesley would have none of this
quasi-magical 19th century engineering and quickly came up
with a solution.

He realised that precision boring spindles have to perform
with a radial runout of better than one tenth of a thou
without adjustment over a period of many months, so decided to
approach the manufacturer of such machine tools and give him
the problem.

Bill Burnham of Burnham and Turners in Mansfield cheerfully
undertook to make a suitable drum mechanism if we provided him
with outline design and details of the motor to be
incorporated. Bill entertained no taboos or superstitions
about putting three bearings on one shaft.

He assured constancy in bearing behaviour and bearing life by
using twin sets of angular contact ball bearings under
considerable axial pressure. As I recall it the original
prototype which was used in the first Pegasus cost only £300,
excluding the electric motor. The drum fitted to the CCS
machine is a later and larger version although it's built on
precisely the same principles.

Other Ferranti drums were run as slaves to the rest of the
machine, synchronised in a phase-lock with crystal controlled
logic circuits, requiring an elegant servo system, and
culminating in a very hefty power amplifier. This was in my
view to turn good design on its head, because you are making a
cumbersome object (a rotating drum) slave to a more pliant
system (a lot of digital circuits). Our drum needed over a
quarter of a horse-power, making this scheme doubly
unattractive.

I therefore got Owen to agree that the logic should be driven
from a clock track recorded on the drum. The rotational speed
of the drum would then be kept within the limits required by
the delay lines, using quite a simple servo loop with a
crystal reference.

As the drum drive had to be at 150 Hz for the 4000 rpm
rotation speed, this loop included the motor excitation of the
150 Hz alternator set. That left us with a small problem: how
do you record a clock track on the magnetic oxide, which is
consistent, the right number of bits, and actually joins
without any bumps?

We accomplished this by first recording an approximately
correct, but incomplete clock track, which was then
temporarily phase-locked by a hand adjustment of the servo. At
the correct rotation speed, using a crystal controlled
reference and using an expanded trace oscilloscope, the
rotational inertia of the drum made this practically possible
without any excessive manual dexterity on the part of the
operator. At first a clock frequency of correct length to
close on itself was then recorded.

Ferranti drums had previously been nickel coated because the
low coercivity required little power output from the write
amplifiers. However these coatings had occasional magnetic
weak or dead spots, owing I believe to stresses in the
plating.

Subsequently when I went to IBM I discovered they had similar
problems at about the same time with their drums on the IBM
650. They eventually overcame them with weird chemicals in the
plating baths. At the BBC however I'd found that Fe2O3 oxide
dispersion used for coating magnetic tape was readily spray
painted onto a drum, using just an ordinary spray gun, and so
we abandoned nickel for red iron oxide.

Split rings of low loss ferrite also worked as well as read
and write heads up to well over 0.5 MHz, needing only pairs of
miniature power pentodes to drive the magnetic oxide into
saturation. Better still, correctly formed ferrite recording
head blanks were then becoming available. I was fortunate in
finding a subcontractor, Epsilon Ltd, making multistack heads
for tape recorders who were willing to package banks of
ferrite heads with a low impedance to my requirements.

Drum system performance, reliability and usability was greatly
increased by abandoning relay head switching and developing
valve and germanium diode crossbar switches for writing and
reading.

The read switch came before any amplification and was entirely
novel. Charles Owen had to be convinced by a test lasting
several months with a random batch of diodes that diode noise
would not cause errors; however diode noise remained below 250
millivolts, and was quite harmless to the unamplified phase
modulated signal of some 3-4 mV from the heads.

These switches meant that the relay switch settling times of
20 milliseconds, which is what you got in a Post Office relay,
were totally avoided; in fact the read amplifier recovery
after writing time of about 500 ms became a limiting factor,
while track switching took only about half that time.

So we both improved the performance and enabled single word as
well as eight word block transfers to be efficient. Lastly,
block addresses in the drum address track were permutated to
leave two blocks between blocks of successive block addresses
within any block where the addresses remain in natural
sequence.

This gave time for some computation between successive blocks
without involving the programmer, and he didn't have to go in
for fancy addressing of his data via optimum programming,
which was in general use for other drum systems.

As a result of these innovations the drum system became in
harmony with the general approach that distinguished the
Strachey-Owen design.

I'll mention two other features of the logical design that
contributed to overall performance. These were the provision
of multiple accumulators and many more registers; and the
incorporation in the order code of a comprehensive and
logically regular method of handling address modification
using some of these extra registers.

How much more effective would Pegasus' contemporary, the IBM
650, have been with these features, designed as it was for
similar user areas? How sad that Pegasus could not have been
equally widely exploited.

That concludes my survey of Pegasus development except to say
as I wrote in the Computer Journal of June 1991, "It is a
matter of record that all of these features were working in
the Pegasus pilot by April 1956.

"Development begun in 1955 added card and tape peripherals in
the subsequent years, leading to machine sales of nearly 40
machines overall. Regardless of these good beginnings an
evident loss of focus on behalf of the Ferranti senior
management, coupled with NRDC's short term financial
preoccupations, fostered an atmosphere in which by 1956 the
burden of continuing investment was only acceptable at a level
requiring a fundamental choice between the Mercury team in
Manchester and the Pegasus team in London.

"Except for the peripheral developments mentioned above the
Pegasus team was largely disbanded, and staff were redirected
to work on Ferranti contract and defence work, or in the case
of some of the leading team members regrouped under American
auspices in September 1956. This was a blow to the infant
British computer industry at a most crucial time from which
subsequent events have shown it never wholly recovered,
exemplifying how inadequate investment ensures a net and
enduring loss."

The history of Pegasus has always seemed to me to be a
paradigm of the British industrial malady - not just the
shibboleth that Britain fails to market its wares, but more
fundamentally that we no longer recognise or foster and
therefore we cannot exploit our real strengths.

This article is based on a talk given by the author as part of
the Elliott/Pegasus all-day seminar at the Science Museum on
21 May 1992.

Working Party Reports

Elliott 401

Chris Burton, Chairman

Conservation has progressed well, with the drum unit, drum
cabinet and monitor console returned to our working area since
the last report in issue 5. Once conserved, we try to remember
to wear gloves when handling items to prevent further
corrosion.

To celebrate the 40th anniversary of the first demonstration
of the Elliott 401, a reception was held in the Science
Museum, welcoming the Director, people connected with the
early days of the machine, and other dignitaries. Parts of the
machine were on display, triggering many recollections.

During our monthly working party meetings, good progress was
being made with recovery of data from the drum surface until
John Cooper's untimely death. We will attempt to continue this
task using the equipment which John had designed and almost
completed. The drum has been run up to 4600 rpm, and it was
satisfying to see data signals from one of the read heads on
an oscilloscope.

As expected, reconstruction of the current logic diagrams is a
difficult and time-consuming job, but headway is being made.
At the same time we will be establishing the current machine
order code, which does not appear to be correct or complete in
any extant documents.

With great trepidation, mains power was applied to the monitor
console (cautiously, through a Variac!), and with one
exception the power supplies worked after changing a couple of
valves. Two resistors were found to be open-circuit in the EHT
power supply, and after replacing those the monitor cathode
ray tubes came to life with splendid bright, sharp traces. A
fine tribute to the original workmanship, for the equipment
has been unused and in store for nearly 30 years.

Pegasus

Chris Burton, Acting Chairman

The working party was saddened by the unexpected death of its
chairman John Cooper in June. The present good state of
Pegasus is largely due to his efforts, and his energy,
enthusiasm, skill and generosity will be very much missed.

Pegasus has been operational on In Steam days during the last
six months, although reliability was poor initially. Many of
the delay line store locations appeared to be marginal and had
to be changed frequently. A thorough investigation
eventually led John to notice that the system clock waveform
derived from the drum had occasional weak signals. Changing to
the Master Clock track cured the unreliability.

We were faced with rewriting the working clock track, which is
a significant task, in unfamiliar territory. However, we
carefully assessed the problem and procedures, found the
required equipment among the spare parts, and created an
operational script to guide us. Happily, the method worked
successfully, allowing program testing work to continue.
Weeding out marginal delay lines can now continue from a more
solid base, and we have gained more useful experience.

We are now expecting Pegasus to be moved to a public gallery,
probably in the autumn. We have started assessing the tasks to
be done to make the move and get operational again.

S-100 bus

Robin Shirley, Chairman

A useful contact has been made with Peter Catley, a computer
consultant who runs the Windsor Bulletin Board as a spare time
activity. Apart from being a kindred spirit and user of
several 8-bit micros, Peter has preserved a number of
microcomputer user group libraries, including those of the UK
CP/M and MSDOS User Groups (the former also held by Emmanuel
Roche in France, as discussed in my last working party report
in issue 5).

Peter and I have agreed to collaborate later this summer on
completing the reorganisation of the UK CP/M library volumes
for storage under MSDOS, which principally involves making
systematic changes to filenames which contain characters that
are illegal under MSDOS. When this work is finished, I shall
then also hold a complete copy of the UK CP/M library for the
use of the S-100 Working Party and the CCS generally.

Apart from the intrinsic value of Peter's work in making this
material more widely available, those in the Society concerned
with software preservation might find much of interest in the
methods that Peter has evolved to deal with the practical
needs of organising and preserving substantial amounts of old
software - that this is currently a hot topic, both for the
Society as a whole and others, is illustrated by Sandy
Douglas' remarks in his Guest Editorial starting on page 3 and
by Doron Swade's article starting on page 13.

DEC

Adrian Johnstone, Chairman

Restoration activity has been suspended until we can re-
establish ourselves at Blythe House, following the Science
Museum's decision to require us to move from the Old Canteen
building (see Society News on page 5). We have already moved
all our systems and equipment to the new location, and it
looks like a good working environment.

A copy of the PDP-8 emulator developed by Colin Smith has been
given to Worcester College of Technology. The College is now
looking for a late model PDP-8, such as a PDP-8/E, to provide
its students with practical experience of the machine. Any
offers would be greatly appreciated.

This emulator is available to anyone who wants it. It runs on
VAX systems, but I am currently porting it to a PC
environment.

Elliott 803

John Sinclair, Chairman

The Elliott 803 is still in the Old Canteen building at the
time of writing, pending a decision by the Science Museum as
to when it should be moved to Blythe House. The processor is
currently in full working order, but there is a fault with the
film handling system which I have so far been unable to trace.

I have stopped work on trying to locate this fault, as I have
no diagrams to work with at present. This is because they are
currently being copied onto microfilm. There is only the one
set of drawings, which are the originals supplied with the
machine when it was new - 30 year old A2 documents.
Microfilming them will allow us to make as many paper copies
as we wish while preserving the originals in at least their
present state.

Another important step we have taken is to make a video which
shows how to disassemble the machine and then put it together
again. Tony Sale wielded the camera while I have provided the
running commentary.

The video shows the best way of undoing the cables, and the
way to mark the cables as they are removed. It shows also how
to turn the machine on once it has been reassembled, a much
more complicated procedure than with today's computers.

It involves taking some of the boards out of the cabinet
before switching on the power supplies and ensuring they all
work. The boards are then put back in batches in a strict
sequence.

Unfortunately, even if the correct procedures are followed
there is no guarantee that the system will then work - indeed,
it is virtually certain that it won't. It is impossible to
explain how to apply the necessary "kiss of life" on a short
video: it took me a 16 week full time course to learn how to
do it when I joined Elliotts in the sixties!

Letters to the Editor

Dear Sir,

Tony Peach's letter in issue 5 reminded me that the Dynamic
Own Array feature in DECsystem-10 Algol 60 did have a use:
implementing Ackerman's function (reasonably) efficiently.
Ackerman's function spends a lot of its time recomputing
previously computed values, so storing them makes sense.
Unfortunately it is not easy to predict what size array is
needed, so a Dynamic Own Array, suitably resized by re-
entering the block in which it is declared, does the job,
reducing the computation time by at least an order of
magnitude for non-trivial cases.

Dynamic Own Arrays were, to the best of my knowledge, only
implemented on two other Algol 60s: a Burroughs
implementation, and one produced at Novosibirsk (USSR as was).
Unfortunately, my co-authors of the documents leading up to
the ISO standard (David Hill and Brian Wichmann) did not agree
that it is a very useful feature, and it did not appear in the
standard, although we did ensure that Own variables were
useful by forcing them to be initialised to zero or FALSE as
appropriate.

My apologies for not writing sooner on this matter, but in the
account of "The Early Days of Algol" in issue 4 there were a
few typographical errors in the part relating to DECsystem-10
Algol 60. "Forced statement" should be "For statement" and
"non real" should be "long real". I am not sure what
"position" in "We put in a few extras: position..." should
have been: the only other thing I can think of is string
variables (including their subscription). Also "remainder,
operator" should be "remainder operator".

By the way, I was certainly not one of the earliest users of
Algol 60 - I learnt it (from a book) in 1964.

Best wishes,

Richard M de Morgan
Padworth Common, Reading
1 March 1993

Dear Mr Enticknap,

I would like to correct the suggestion made in the letter by
Tony Peach in your Spring 1993 issue that the two Algol
compilers developed for the KDF9 at Kidsgrove and Whetstone
were produced by teams who were in ignorance of each other's
efforts.

I was in charge of the Whestone compiler project though
Lawford Russell and I worked very much as a team. From the
outset there was a full agreement with the Kidsgrove group
that we would develop a system which emphasised compiler speed
and which was intended principally for program development,
whilst they would produce a very sophisticated optimising
compiler.

Thanks in particular to the good offices of Fraser Duncan at
Kidsgrove the coordination remained close. One unplanned but
very beneficial effect was that any technical disputes were,
wherever possible, resolved by reference to the Algol 60
report. As a result our compiler was, to my knowledge, one of
the most pedantically complete that was ever produced, and
handled the full generality of for statements, call by name,
own variables, recursion, etc. As a result we were able to
announce its completion by publishing a certification of Tony
Hoare's Quicksort algorithm (which he had described
recursively but could only test on the Elliott 803 via a hand-
converted iterative version), and to use Don Knuth's
horrendous "Man or Boy" algorithm showing the complications
of call by name, etc, as the main worked example in our book
Algol 60 Implementation.

Yours sincerely,

Brian Randell
University of Newcastle
30 June 1993

Dear Nicholas,

Tony Sale's paper in the Summer 1993 issue of Resurrection
gave a good account of the Enigma story at Bletchley Park (B-
P), but in the section headed "Heath Robinsons" there were
confusions that have been repeated many times since they first
arose in the "Secret War" TV series. I would like to tell
you a small part of the true story because you are surely
devoted to historical truth in your journal.

The term Geheimschreiber is often used, but it is not the
official designation of any German cipher system. There were
actually two online Baudot code cipher systems in use, and
most accounts have confused them.

One was a modified telex machine called T typ 52, made by
Siemens and Halske. This could transform either keyboarded
messages or punched paper tape messages into 5-unit enciphered
telegraph characters on a pair of wires, and it could receive
such a signal and decipher it, producing a printed paper
strip. The T52 was mostly used on land lines and therefore the
opportunity for B-P to attack it was very limited. I have been
told that it "was never routinely broken".

When Norway was occupied, T52 transmissions via Sweden were
intercepted and broken, but how much and whether the allies
benefited is unknown to me. Late in the war some T52 traffic
was sent by radio and may have been processed at B-P; I do not
know.

Much more important to the Allied cause was a different cipher
system known as Schluessel Zusatz or cipher attachment, either
SZ40 or SZ42. This machine was made by Lorenz. I have tracked
down two existing machines, one now in the DeutschesMuseum and
the other in the Norwegian Armed Forces Museum. This system
was used by the Wehrmacht for high level traffic by radio and
was the target for the highly successful and valuable work of
the Heath Robinsons and Colossi.

The SZ machine received a 5-unit telegraph signal, converted
it into a five wire form, enciphered or deciphered it and then
retransmitted it in the serial telegraph form. Therefore it
was always used in-line, between normal teletype machines and
their radio link. The intercepted traffic was called Fish, and
much of B-P's work on it is described in Hinsley's official
history. Several times, changes were made in the SZ machines
and countered by hard work at B-P.

Dr Huettenhain of the OKW (Oberkommando der Wehrmacht) cipher
bureau made a comparative study of the security of the T52 and
SZ systems at the start of the war. He would not tell me the
result but I suspect that the T52, in its later forms, was the
more secure. The SZ was nevertheless chosen for the most
sensitive application and I can only guess that this was
because of the immense bulk and weight of the T52.

It has become customary to refer to the T52 as a
Geheimschreiber, though people who used it in WWII do not seem
to recognise the term. We should be quite clear that this
machine was not the source of the Fish traffic broken by the
Colossi.

Aims and objectives

The Computer Conservation Society (CCS) is a co-operative
venture between the British Computer Society and the Science
Museum of London.

The CCS was constituted in September 1989 as a Specialist
Group of the British Computer Society (BCS). It thus is
covered by the Royal Charter and charitable status of the
BCS.

The aims of the CCS are to

Promote the conservation of historic computers

Develop awareness of the importance of historic
computers

Encourage research on historic computers

Membership is open to anyone interested in computer
conservation and the history of computing.

The CCS is funded and supported by, a grant from the BCS, fees
from corporate membership, donations, and by the free use of
Science Museum facilities. Membership is free but some charges
may be made for publications and attendance at seminars and
conferences.

There are a number of active Working Parties on specific
computer restorations and early computer technologies and
software. Younger people are especially encouraged to take
part in order to achieve skills transfer.

The corporate members who are supporting the Society are
Allied Business Systems, Bull HN Information Systems, Digital
Equipment, ICL, Unisys and Vaughan Systems.

Resurrection is the bulletin of the Computer
Conservation Society and is distributed free to members. Additional
copies are £3.00 each, or £10.00 for an annual
subscription covering four issues.